Abstract

Colon cancer (CC) is an important contributor to worldwide cancer mortality and morbidity as there are about 1.2 million new cases diagnosed and 0.6 million deaths from this disease reported every year around the world. Racial disparities in incidence of CC have emerged and widened for the past three decades with Native Americans form a unique cohort of CC patients among whom the variability in demographics and cancer characteristics remain unclear. The aim of this study was to assess the variability in demographics and characteristics among Native American patients with CC in the United States.

Methods: We abstracted the national estimates for patients with diagnosis of CC using the Surveillance, Epidemiology, and End Result (SEER) database between 2000 and 2012. Native American patients with CC were included in study and stratified into groups based on the year of initial diagnosis, gender, location of cancer in colon (ascending, transverse and descending), stage of disease and insurance status. Outcome measures such as CC incidence, variation in location and patient demographic analysis along with trend analysis were performed.

Results: A total number of 355,115 patients with CC including all racial/ethnic groups were reported during the 12-year study period. From these cases, 6.9% (n=26,674 were CC cases from Native Americans. While the overall incidence rates of CC decreased by 12% (28.3% in 2000 to 24.7% in 2012, p=0.01) during the study period, incidence rates increased by 38% in a group of Native Americans (from 5.3% in 2000 to 8.4% in 2012, p=0.004). Incidence of CC was more prevalent in Native American females than males (p=0.02). There was higher increase seen in females (42%) compared to males (34%) over the 12-year period. The highest incidence of stage III CC tumors (29%) was observed with sigmoid colon being the most common site location of CC (38%) in this racial/ethnic group. 72% of all CC tumors were moderately differentiated, with 55% tumors localized in left, 36% in right and 9% in transverse colon. 92% of the Native American patients were insured.

Conclusions: Demographic and disease variability exists among Native American patients with CC in the United States. The incidence of CC among Native American continues to rise in the past decade despite national decreasing trends. Furthermore, patients continue to present at higher stage of colon cancer with moderate differentiation. Further research is required to understand the reasons for the differences among Native American patients with CC to help improve patient outcomes.